Mechanically controlled hydraulic system for an agricultural implement

ABSTRACT

A hydraulic control apparatus for a foldable farm includes first hydraulic control system is used to control weight transfer to ground engaging tools mounted to a stationary and foldable wing frame sections. A second hydraulic system is used to fold and unfold the wing sections. A hydraulic control is provided that interfaces with both hydraulic systems to control sequencing of the functions provided by the first and second hydraulic systems. The first and second hydraulically systems have mechanically controlled valves to control the flow of hydraulic fluid to various lifting, folding, and down pressure cylinders.

BACKGROUND OF THE INVENTION

The present invention relates generally to farm implements and, moreparticularly, a hydraulic control system for a foldable farm implement.

Modern farmers strive to improve the management of the increasingamounts of farm acres. Improving management requires farmers to be ableto quickly prepare the soil and plant seed each season. This haste hasdriven the need for more efficient and larger agricultural machinery.

Implements such as harrows, packers, or combined harrow-packers arebeing made with widths exceeding sixty feet in the field operatingposition. Also, drill implements employed to distribute seed productacross an agricultural field are also being made increasingly wider inthe field operating position. Wider working widths provide moreefficient field working such as by increasing the number of rows thatare seeded in a single pass or by increasing the amount of field that istilled in a single pass. However, as agricultural implements have beenmade increasingly wider, there has been a need for systems to compactlyfold the implement for practical and safe transport over highways andthrough gates, and for greater maneuverability. These systems typicallyconsist of hydraulic cylinders and valves that are controlled by aremote operator control to fold and unfold the implement.

Moreover, with agricultural implements, such as hoe drills, requiringfluid power (hydraulic) circuits to perform an increasing number ofother tasks, a greater number of control interfaces are similarlyrequired. The increased number of control interfaces adds to thecomplexity of the overall hydraulic system and reduces space within theoperator cab of the towing vehicle for the implement for other implementcontrols. A narrow transport hoe drill, for example, will be capable ofperforming several hydraulically powered functions, such as raising andlowering the ground engaging tools, e.g., openers, applying a trip forceon the ground engaging tools, and setting the amount of packing pressurethat is applied by the packer wheels. Additionally, as noted above, thewing sections of the hoe drill, which are mounted to opposite lateralsides of a stationary frame section, are hydraulically folded to atransport position and hydraulically lowered from the transport positionto an extended, unfolded position. A down pressure is also typicallyhydraulically applied to the stationary frame section and the wingsections to prevent the frame sections from pivoting upward due to theresultant force from the ground engaging tools. Moreover, as an air cartis typically used with seeding implements, air cart functions, such asfan operation and seed metering will require hydraulic control.

SUMMARY OF THE INVENTION

The present invention is directed to a hydraulic control apparatus for afoldable farm implement that overcomes some of the drawbacks associatedwith conventional hydraulic systems. The farm implement generallycomprises a stationary frame section and a pair of wing sectionspivotably mounted to opposed lateral sides of the stationary framesection. A first hydraulic control system is used to control weighttransfer to the ground engaging tools mounted to the stationary and wingframe sections. A second hydraulic system is used to fold and unfold thewing sections. A hydraulic control is provided that interfaces with bothhydraulic systems to control sequencing of the functions provided by thefirst and second hydraulic systems.

One of the objects of the invention is to provide a less complexhydraulic control for folding and unfolding wing sections of a foldablefarm implement and lowering ground engaging tools of the foldable farmimplement to a ground engaging position.

Another object of the invention is to provide a single remote hydrauliccontrol for controlling a first hydraulic system that controls weighttransfer to the ground engaging tools and a second hydraulic system thatcontrols folding and unfolding of the foldable wing sections.

It is yet another object of the invention to provide a remote hydrauliccontrol that is operative to disable a first set of hydraulic cylindersthat lower the ground engaging tools when the wing sections are beingmoved to a folded position by a second set of hydraulic cylinders and isfurther operative to control the second set of hydraulic cylinders toprevent folding the machine when the ground engaging tools are in theground engaging position.

Other objects, features, aspects, and advantages of the invention willbecome apparent to those skilled in the art from the following detaileddescription and accompanying drawings. It should be understood, however,that the detailed description and specific examples, while indicatingpreferred embodiments of the present invention, are given by way ofillustration and not of limitation. Many changes and modifications maybe made within the scope of the present invention without departing fromthe spirit thereof, and the invention includes all such modifications.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred exemplary embodiments of the invention are illustrated in theaccompanying drawings in which like reference numerals represent likeparts throughout.

In the drawings:

FIG. 1 is a pictorial view of a farm planting system having a farmimplement hitched to a prime mover;

FIG. 2 is a top isometric view of a hoe drill in an unfolded, workingposition for use with the farm planting system of FIG. 1, and shownwithout ground engaging tools;

FIG. 3 is an isometric view of the hoe drill in a folded, transportposition;

FIG. 4 is a rear isometric view of a front portion of the hoe drill;

FIG. 5 is an enlarged view of the front portion of the hoe drill;

FIG. 6 is a front isometric view of a center section of the hoe drill;

FIGS. 7A and 7B are isometric views of a valve lockout arrangementaccording to one aspect of the present invention;

FIG. 8 is a schematic representation of a first preferred hydrauliccontrol system for the hoe drill;

FIG. 9 is a schematic representation of a second preferred hydrauliccontrol system for the hoe drill;

FIG. 10 is a schematic representation of a third preferred hydrauliccontrol system for the hoe drill; and

FIG. 11 is an isometric view of a valve-actuating rockshaft of the drillshown in FIG. 2; and

FIG. 12 is a section view taken along line 12-12 of FIG. 7A.

DETAILED DESCRIPTION

Referring now to FIG. 1, a planting system 10 according to oneembodiment of the invention includes a foldable implement 12, shown in afield working position, coupled to a prime mover 14, e.g., tractor, in aknown manner. The planting system 10 may also include an air cart 15, asknown in the art. While the invention is applicable with different typesof foldable implements, for purposes of illustration, the invention willbe described with respect to a hoe drill.

Referring now to FIG. 2, hoe drill 12 has a center frame section 14 andtwo wing sections 16, 18 pivotally mounted to opposite lateral sides ofthe center frame section 14. The wing sections 16, 18 are designed to befolded to a transport position in which the wing sections 16, 18 arefolded over the center frame section 14 to provide a narrow transportconfiguration that is suited for transport between crops, fields, andalong roadways, as well as storage. FIG. 3 shows the hoe drill 12 in thefolded, transport position.

The center frame section 14 has a tool bar 20 to which a tongue section24 is coupled. The tongue section 24 generally consists of a cage 26having a distal end coupled to the tool bar 20 and a proximate endforming a hitch point 28 for coupling to the prime mover 14 in aconventional manner. Wing sections 16, 18 have respective booms 30, 32and draft links 34, 36 are interconnected between the cage 26 and booms30, 32, respectively. The draft links 34, 36 are pivotally connected tothe cage 26 and the wing booms 30, 32 so that as the wing booms 30, 32are drawn inwardly the draft links 34, 36 are drawn to a foldedposition, as shown in FIG. 3.

The center frame section 14 has a tool bar 20 to which a tongue section24 is coupled. The tongue section 24 generally consists of a cage 26having a distal end coupled to the tool bar 20 and a proximate endforming a hitch point 28 for coupling to the prime mover 14 in aconventional manner. Wing sections 16, 18 have respective booms 30, 32and draft links 34, 36 are interconnected between the cage 26 and booms30, 32, respectively. The draft links 34, 36 are pivotally connected tothe cage 26 and the wing booms 30, 32 so that as the wing booms 30, 32are drawn inwardly the draft links 34. 36 are drawn to a foldedposition, as shown in FIG. 3.

Referring again to FIGS. 2 and 4, wing section 16 has a right-hand sidesub-frame 46 that is pivotally coupled to the wing boom 30, and issupported above the field surface by wheels 48. Ground engaging tools(not shown) are attached to the sub-frame 46 in a known manner.Interconnected between the wing boom 30 and the sub-frame 46 are liftcylinders 50, and when appropriate actuated, pivot the sub-frame 46about pivot connections 52 to position the sub-frame generally over wingboom 30. Cylinders 50 also apply a downforce on the sub-frame 46 tolower the openers into engagement with the ground.

In a similar manner, wing section 18 has a left-hand side sub-frame 54that is pivotally coupled to the wing boom 32, and is supported abovethe field surface by wheels 56. Ground engaging tools (not shown) areattached to the sub-frame 54 in a conventional manner. Interconnectedbetween the wing boom 32 and the sub-frame 54 are lift cylinders 58 thatwhen actuated, pivot the sub-frame 54 about pivot connections (notshown) to raise the sub-frame 54 over wing boom 32. Cylinders 58 alsoapply a downforce on the sub-frame 54 to lower the openers intoengagement with the ground

As best shown in FIG. 4, the hoe drill 12 also includes a right-handside folding cylinder 60 and a left-hand side folding cylinder 62. Thecylinders 60, 62 are interconnected between the wing booms 30, 32 andcenter tool bar 20, respectively. More particularly, a mounting flange64 is formed on the rear surface of the center tool bar 20 and inwardends of the cylinders 60, 62 are pivotally coupled to the mountingflange at pivot points 66, 68, respectively. Outward ends of thecylinders 60, 62 are pivotally coupled to mounting flanges 70, 72,respectively, attached to wing booms 30, 32, respectively, at pivotpoints 74, 76, respectively. When the cylinders 60, 62 are appropriatelyactuated, the cylinders 60, 62 pull the wing booms 30, 32 inwardly(rearward) so that the wing booms 30, 32 rotate about knuckles 78, 80 atopposite ends of the center tool bar 20, respectively.

Now referring to FIG. 4, the cage 26 is formed by two pairs of stackedrails 82, 83, 84, and 85 interconnected between center tool bar 20 andhitch point 28. The stacked rails 82, 83, 84, and 85 are angled inwardlyfrom their connection with the tool bar 20 to the hitch point 28 so thatthe cage 26 has a generally triangular form. The cage 26 also includes anumber of cross-bars 86 and posts 88 providing support for the stackedrails 82, 83, 84, and 85. As best shown in FIG. 5, the cage 24 includesa swing mount 90 that is interconnected between the pair of stackedrails. A pair of links 92, 94 are pivotally coupled to the swing mount90 and hook around forward ends of the arms 34, 36. Swing cylinders 96,98 are interconnected between the links 92, 94, respectively, and upperrails 82 and 84, respectively. Thus, when the cylinders 96, 98 areactuated, the links 92, 94 are rotated so as to open and release arms34, 36 allowing the arms 34, 36 to follow the wing sections 16, 18 asthey pivot about knuckles 78, 80. The flow of hydraulic fluid tocylinders 96, 98 is controlled by V4 and V8, or 2A and 2B depending onschematic. See FIGS. 8 and 9.

Now referring to FIG. 4, the cage 26 is formed by two pairs of stackedrails 82, 83, 84, and 85 interconnected between center tool bar 20 andhitch point 28. The stacked rails 82, 83, 84, and 85 are angled inwardlyfrom their connection with the tool bar 20 to the hitch point 28 so thatthe cage 26 has a generally triangular form. The cage 24 also includes anumber of cross-bars 86 and posts 88 providing support for the stackedrails 82, 83, 84, and 85. As best shown in FIG. 5, the cage 26 includesa swing mount 90 that is interconnected between the pair of stackedrails. A pair of links 92, 94 are pivotally coupled to the swing mount90 and hook around forward ends of the arms 34, 36. Swing cylinders 96,98 are interconnected between the links 92, 94, respectively, and upperrails 82 and 84, respectively, Thus, when the cylinders 96, 98 areactuated, the links 92, 94 are rotated so as to open and release arms34, 36 allowing the arms 34, 36 to follow the wing sections 16, 18 asthey pivot about knuckles 78, 80. The flow of hydraulic fluid tocylinders 96, 98 is controlled by V4 and V8 depending on schematic. SeeFIGS. 8 and 9. The pressure reducing valve 100 controls the pressureapplied to the weight transfer system.

FIG. 8 is schematic of the hydraulic circuit for controlling raising andlowering and folding and unfolding of the hoe drill 12. The circuit 124includes a set of pressure reducing/relieving valves 125 that controlthe hydraulic pressure on the base end of the tool frame cylinders 42,50, and 58, and the opener cylinders 126. Valves V1, V2, V3, and V4 arecontained within valve bodies 108, 110, 106, and 104, respectively.Valves V1, V2 are used to lock out the opener cylinders when the drill12 is not in the working (field) position. In this regard, when valvesV1, V2 are closed the openers cannot be lowered. Valve V3 is in the leftposition when the machine is in the working position. This is requiredto allow hydraulic fluid to return from the rod end to the base of thetool frame cylinder 42, 50, 58, and so fluid can return to accumulator128. Valve V4 allows fluid to pass to and from the hydraulic system (notshown) of the prime mover, e.g., tractor. It will thus be appreciatedthat the hydraulic circuit 124 has a pair of supply ports 130, 132 andreturn ports 134, 136.

In the embodiment illustrated in FIG. 8, the hydraulic circuit 124includes two sub-circuits. A frame circuit for controlling thesequencing of the folding and unfolding of the drill as well as raisingand lowering the openers, and a swing circuit for controlling swingingthe wing booms inward to the transport position and outward to theworking position. Each sub-circuit is activated by separate remotecontrols 138 and 140.

In this regard, when the operator desires to fold the implement, theoperator moves the control lever 120 to the transport position, whichresults in rotation of the rockshaft. With rotation of the rockshaft,valves V1, V2 are moved to the closed position, valve V3 is in the righthand position, and valve V4 is in the right hand position. Then usingthe remote control, the operator can commence folding of the drill. Moreparticularly, the right-hand side of the drill is first raised byactivating remote 138. The operator can swing the right-hand side wingboom 16 inward using remote control 140. This causes V5 to open, and V6to close. The left-hand side of the drill may now be rotated upward sothat the left-hand side sub-frame is rotated over wing boom 18. Thismoves V8 to the left position. Wing boom 18 may then be swung inward toplace the drill in the transport position shown in FIG. 3. Becausevalves V6 and V7 are one-way blocking (check) valves when closed,pressure can be supplied to the rod end. This allows the operator toraise the sub-frames if they have lowered due to internal valve leakage.

One skilled in the art will appreciate that to unfold the drill 12 fromthe transport position to the working position, the operator again usesremote control 138 to commence the unfolding process. First, the leftwing boom is pivoted outwardly to the extended position. Thereafter, theleft sub-frame, right wing boom, and then right sub-frame are extendedand lowered to the position shown in FIG. 2. The operator then moves thecontrol lever 120 to the working setting. This causes rotation of therockshaft, which in turn causes valves V1 and V2 to open to extend theopener cylinders for lowering the openers into engagement with theground. Valve V3 is also moved to the open position which allows thesub-frames to move in response to changes in ground contours. Valve V4is moved to the closed position.

It will be appreciated that the hydraulic circuit 124 provides acontrolled sequencing of the folding and unfolding of the drill 12 usinga network of shut-off and sequencing valves that are mechanically linkedto open and close in a prescribed order. It will further be appreciatedthat the circuit 124 also permits one hydraulic remote, e.g., remote138, to be used to control the weight transfer for the sub-frames,ground engaging tool tip force and packing force, in addition to raisingand lowering of the sub-frames. More particularly, the pressure controlvalves include valves V9 and V10 that allow the frame weight transferand opener tip force to be set at different levels.

Using one remote control for weight transfer and tip and packing forceprovides a timing benefit. That is, when the openers are lowered andengaged in the ground, weight transfer to the frames should be applied.On the other hand, when the openers are in the raised position, weighttransfer should be removed to reduce stress on the sub-frames. By usinga single remote, this application and reduction of weight transfer willalways occur. Additionally, when folding into the transport position,the openers will be raised fully off the ground before the sub-framesare lifted off the ground. Thus, the possibility of the operatorforgetting to raise the openers before transport is avoided. As aresult, the circuit 124 ensures that no openers are too low before thedrill is folded to the transport position.

In other words, utilizing a single control for the pressure reliefsub-circuit and the shut-off/sequencing sub-circuit provides: (1) noweight transfer to the sub-frames will occur until the openers arelowered; (2) all weight transfer to the sub-frames will be removedbefore the openers are raised; (3) openers will be raised before thesub-frames are raised; and (4) the sub-frames will be lowered before theopeners are lowered into ground engagement.

FIG. 9 is a schematic layout of another preferred hydraulic circuit foruse with the drill shown in FIG. 2. In this embodiment, the circuit 142is substantially similar to circuit 124 described above, but utilizessolenoid controlled valves rather than mechanically actuated valves tocontrol the raising and lowering and folding and unfolding of the drill.

FIG. 10 shows yet another schematic layout of a preferred hydrauliccircuit 144 according to another aspect of the invention. In thisembodiment, which for purposes of illustration has a layout similar tothe circuit of FIG. 9, the swing circuit and the frame circuit are onthe same remote 146. Thus, in this embodiment, a single hydraulic remotecontrol may be used to control raising and lowering of the openers,raising and lowering of the sub-frames, and swinging in and out the wingbooms. Circuit 144 includes ON/OFF valve 148 to activate/deactivate theswing sub-circuit.

As described above, one of the drawbacks of conventional foldableimplements is the possibility that the implement frame could beunintentionally lowered while in the transport position. If the valvesare switched to the field setting while the implement is transitioning,or is already in, the transport position, the implement frame could befree to pivot and lower without control. To prevent such an occurrence,the present invention provides a lockout arrangement 150, which is bestillustrated in FIGS. 7A and 7B.

The lockout arrangement 150 generally consists of a push-pull cable 152and a sliding pin 154. The sliding pin 154 is attached to an end of thepush-pull cable 152 adjacent the rockshaft 112. The opposite end of thepush-pull cable 152 is attached, at point 156, to one of the wingsections, such as sub-frame 46.

Alternately, the push-pull cable 152 could be attached to sub-frame 54.In either case, when the implement is in the field position, e.g., thewing sections 16, 18 are unfolded and all sub-frames are lowered, suchas illustrated in FIG. 2, the center tool bar and the wing booms aregenerally parallel to the ground and is free to rotate approximately 15degrees away from or toward the ground to account for changes in groundcontours, field obstructions, and the like. When the operator desires toplace the implement in its transport position, the operator activatescontrol lever 120 which causes rotation of the rockshaft 112. As therockshaft 112 rotates, the positions of the valves 104-110 change, asdescribed above. In one preferred embodiment, after the control leverhas been activated to change the valves to the “transport” setting, theoperator activates the remote control that causes the right-hand sidesub-frame to rotate over the wing boom 30 followed by swinging in of thewing boom 30

As sub-frame 46 is rotated, the lockout arrangement 150 of the presentis activated. More particularly, as sub-frame 46 rotates over tool bar30, the attached end of the push-pull cable 152 pushes the cable inward,i.e., toward the rockshaft 112. With continued rotation of thesub-frame, the pin 154 moves toward a bore 158, FIG. 11, formed in anend of the rockshaft 112. When the sub-frame 46 has reached its fullyrotated position, the pin 154 will slide into the rockshaft 112 therebypreventing rotation of the rockshaft 112. As a result, if the controllever 120 were to be activated while the implement is folding or hasbeen folded, the rockshaft 112 will not be allowed to rotate. Since therockshaft 112 is prevented from rotating, the valves controlled byrotation of the rockshaft 112 cannot change positions. Most importantly,since valves V1 and V2 are closed when the rockshaft 112 rotated bymovement of the control lever 120 to the transport setting, locking outrotation of the rockshaft 112 prevents unintentional movement of therockshaft 112 to the “working” setting via movement of the control lever120. Since hydraulic fluid cannot flow, the implement cannot rotate orpivot as may otherwise occur without the lockout arrangement 150 of thepresent invention. When the implement is unfolded, the pin 154 willautomatically be withdrawn from the rockshaft 112 which allows therockshaft 112 to rotate when the control lever is moved to the “workingposition”.

The lockout arrangement 150 includes a flange 160 mounted to the toolbar 20 and adjacent to the bore 158 formed in the end of the rockshaft112. The flange 160 carries a bushing 162 that aligns with bore 158 whenthe rockshaft 112 is rotated to the transport position. The pin 154slides within bushing 162 as the wing section 16 is folded. As describedabove, when fully folded, the pin 154 will slide through the bushing 162into the bore 158 of the rockshaft 112. Since the bushing 162 is mountedto the flange 160, which is fixedly attached to the tool bar 20,rotation of the rockshaft 112 will be prevented when pin 154 ispositioned within the bore 158.

It will be appreciated that the present invention provides a hydrauliccircuit for use with a farm implement, such as a hoe drill, whichprovides a number of performance benefits over conventional hydrauliccircuits or systems. The hydraulic circuit is arranged and configured tosequence the raising and lowering and folding and unfolding of theimplement in a predefined, orderly manner. Weight transfer to the framesof the implement, opener tip force and packing force, andraising/lowering of the frames and transitioning between field andtransport position can be controlled using a single remote. Using asingle remote also provides a preferred sequencing of theapplication/removal of weight to the frames and raising/lowering of theimplement. In one embodiment, a single remote control can be used tocontrol both a frame lowering/raising circuit and a boom swing circuit.Further, according to another aspect of the invention, a valve lockoutarrangement is provided to prevent the flow of hydraulic fluid to thecylinders that raise and lower the openers when the implement is in, orbeing transitioned to, the transport position.

Many changes and modifications could be made to the invention withoutdeparting from the spirit thereof. The scope of these changes willbecome apparent from the appended claims.

Many changes and modifications could be made to the invention withoutdeparting from the spirit thereof. The scope of these changes willbecome apparent from the appended claims.

I claim:
 1. A hydraulic control apparatus for an agricultural implement,the implement having a stationary frame and a number of foldable framesections pivotably coupled to the stationary frame, and a plurality ofground engaging tools mounted to the stationary frame and the number offoldable frame sections, the apparatus comprising: a fluid supply portfor coupling to a fluid supply line of a towing vehicle; a fluid returnport for coupling to a fluid return line of the towing vehicle; a firsthydraulic system that controls weight transfer to the plurality ofground engaging tools, the first hydraulic system in fluid communicationwith the fluid supply port and the fluid return port, and including afirst set of mechanically controlled hydraulic valves; a secondhydraulic system that controls folding and unfolding of the number offoldable frame sections, the second hydraulic system in fluidcommunication with the fluid supply port and the fluid return port, andincluding a second set of mechanically controlled hydraulic valves; anda linkage arrangement that mechanically opens and closes the second setof mechanically controlled hydraulic valves in response to movements ofthe number of foldable frame sections.
 2. The apparatus of claim 1wherein the first and the second hydraulic systems are configured suchthat an instruction from a respective one of a pair of hydraulic remotecontrols to unfold the number of foldable frame sections causes thefirst hydraulic system to prevent weight transfer to the pluralityground engaging tools until the second hydraulic control system hascompleted unfolding of the number of foldable frame sections.
 3. Theapparatus of claim 1 wherein the first and the second hydraulic systemsare configured such that that an instruction from a single remotehydraulic control to lower the plurality of ground engaging tools into aground engaging position causes the first hydraulic system to transferweight to the ground engaging.
 4. The apparatus of claim 3 wherein thesecond hydraulic system is configured to remain disabled until the firsthydraulic system has been instructed by the single remote hydrauliccontrol raise the plurality of ground engaging tools from the groundengaging position.
 5. The apparatus of claim 4 wherein the first and thesecond hydraulic systems are configured such that an instruction fromthe single remote hydraulic control to fold the number of foldable framesections causes the first hydraulic system to raise the plurality ofground engaging tools from the ground engaging position and thereaftercauses the second hydraulic system to fold the number of foldable framesections.
 6. The apparatus of claim 5 wherein the first hydraulic systemcomprises a first plurality of cylinders mounted to the stationary frameand number of foldable frame sections, and configured to lower theground engaging tools into the plurality of ground engaging position. 7.The apparatus of claim 6 wherein the second hydraulic system comprises asecond plurality of cylinders interconnected between a booms andsub-frames, and a third plurality of cylinders interconnected betweenthe stationary frame section and the number of foldable frame sections,and configured to raise and lower the number of foldable frame sectionsto fold and unfold the number of foldable frame sections.
 8. Theapparatus of claim 7 wherein the first set of mechanically controlledhydraulic valves includes first and second shut-off valves fluidlycoupled to the second plurality of cylinders and operative to controlthe flow of hydraulic fluid between a fluid source and the firstplurality of cylinders.
 9. The apparatus of claim 8 wherein the secondset of mechanically controlled hydraulic valves includes an arrangementof sequencing valves.
 10. The apparatus of claim 7 further comprising anaccumulator to which fluid may be delivered to temporarily relievepressure in the second plurality of cylinders when a field obstructionis encountered during towing of the implement.
 11. A hydraulic controlsystem for use with an agricultural implement frame, the frame having acenter frame section and a first and a second wing sections mounted toopposite lateral sides of the center frame section, and further havingground engaging tools mounted to the center frame section and the wingsections, the system comprising: a first set of hydraulic cylindersmounted to the implement frame and configured to lower the groundengaging tools into a ground engaging position; a first set of hydraulicvalves associated with the first set of hydraulic cylinders andconfigured to control flow of pressurized hydraulic fluid to the firstset of hydraulic cylinders; a second set of hydraulic cylinders mountedto the implement frame configured to fold and unfold the first andsecond wing sections; a second set of hydraulic valves associated withthe second set of hydraulic cylinders and configured to control flow ofpressurized hydraulic fluid to selective ones of the second set ofhydraulic cylinders; a hydraulic control operative to initiate movementof the first and second wing sections, wherein the first set ofhydraulic valves are caused to disable the first set of hydrauliccylinders when the wing sections are being moved to a folded position bythe second set of hydraulic cylinders and the second set of hydraulicvalves are caused to disable the second set of hydraulic cylinders whenthe ground engaging tools are in the ground engaging position; and alinkage arrangement that mechanically opens and closes the first andsecond sets of hydraulic valves in response to movements of the wingsections.
 12. The hydraulic control system of claim 11 wherein a remotehydraulic control is further operative to re-pressurize the second setof hydraulic cylinders when there is internal leakage in the second setof valves when the first and second wing sections are in a foldedposition.
 13. The hydraulic control system of claim 12 wherein the firstset of hydraulic valves includes shut-off valves and wherein the secondset of hydraulic valves includes an arrangement of sequencing valvesthat control the flow of hydraulic fluid to the second set of hydrauliccylinders in a predefined order such that the first wing section israised to its folded position before the second wing section is raisedto its folded position.
 14. The hydraulic control system of claim 13wherein the hydraulic control is further operative to close the firstset of hydraulic valves when a second set of actuators are raising orlowering the wing sections.
 15. The hydraulic control system of claim 14wherein the hydraulic control is further configured to close the secondset of hydraulic valves when a first set of actuators have lowered theground engaging tools to the ground engaging position.
 16. The hydrauliccontrol system of claim 11 further comprising first and second pressurereducing and relieving valves that can be selectively open and closed toallow the hydraulic control to independently set how much weight istransferred to the implement frame and how much trip pressure is appliedon the ground engaging tools.
 17. An agricultural implement comprising:a tool bar having a stationary frame section adapted to be coupled to atowing vehicle and first and second wing sections pivotably coupled toopposite lateral sides of the stationary frame section; a plurality ofground engaging tools mounted to the tool bar; and a mechanicallycontrolled hydraulic control system for controlling movement of the toolbar, the control system having: a fluid supply port for coupling to afluid supply line of the towing vehicle; a fluid return port coupling toa fluid return line of the towing vehicle; a first set of hydrauliccylinders interconnected between the tool bar and the plurality ofground engaging tools, and configured to move the plurality of groundengaging tools to a ground engaging position; a second set of hydrauliccylinders interconnected between the first and second wing sections andthe stationany frame and configured to move the first and second wingsections between a working position and a folded position; and a linkagearrangement that mechanically opens and closes mechanically controlledhydraulic valves to control hydraulic fluid flow to the first and secondsets of hydraulic cylinders in response to movements of the number orfoldable frame sections.
 18. The implement of claim 17 furthercomprising single hydraulic control for initiating operation of thehydraulic control system, and wherein the first set of hydrauliccylinders are disabled when the first and second wing sections are beingmoved to a folded position by the second set of hydraulic cylinders andthe second set of hydraulic cylinders are disabled when the plurality ofground engaging tools are in the ground engaging position.
 19. Theimplement of claim 18 further comprising a first set of valvesassociated with the first set of hydraulic cylinders and configured tocontrol flow of pressurized hydraulic fluid to the first set ofhydraulic cylinders and further comprising a second set of valvesassociated with the second set of hydraulic cylinders and configured tocontrol flow of pressurized hydraulic fluid to the second set ofhydraulic cylinders, and wherein a remote hydraulic control is furtheroperative to re-pressurize the second set of hydraulic cylinders whenthere is internal leakage in the second set of valves when the first andsecond wing sections are in the folded position; wherein the first setof valves includes shut-off valves and wherein the second set of valvesincludes an arrangement of sequencing valves that control the flow ofhydraulic fluid to the second set of hydraulic cylinders in a predefinedorder such that the first wing section is raised to its folded positionbefore the second wing section is raised to its folded position; andwherein the linkage arrangement is further operative to close the firstset of valves when a second set of actuators are raising or lowering thefirst and second set wing sections.